Per Diem Calculator – Daily Travel Allowance, M&IE, Lodging & International Trips
The Per Diem Calculator helps employees, freelancers and employers plan travel allowances. Instead of guessing totals from per diem tables and policy documents, this tool translates daily rates, partial day percentages and lodging rules into clear trip totals. It supports simple domestic trips and more complex international itineraries.
Per diem systems are widely used because they provide predictable travel reimbursement without collecting every meal and taxi receipt. However, multiple elements influence the final allowance: daily M&IE rates, lodging caps, partial first and last days, and different rates for different cities or countries. This calculator brings those pieces together so you can understand how much a trip will cost and how a policy will affect budgets.
How the Per Diem Calculator Works
The calculator is organized into five practical modes:
- Standard Per Diem: Quick total for daily per diem, full days and partial days.
- Meals & Incidentals (M&IE): Separate meals and incidentals, including credits for provided meals.
- Lodging: Nightly lodging totals with local taxes and fixed hotel fees.
- Partial Travel Days: First and last day calculations using adjustable percentages.
- International Per Diem: Multi-location travel with different daily rates and durations.
The tool does not contain built-in per diem tables. Instead, you enter the daily rates from your employer, contract or government schedule and the calculator handles the arithmetic.
Mode 1: Standard Per Diem Calculator
The standard mode provides a quick estimate of total per diem for a trip that uses one daily rate. You enter the full per diem rate, number of full travel days, number of partial days and the percentage applied to partial days. Many policies pay 75 percent of the full rate on the first and last day of travel; this is the default here, but you can override it.
Standard Per Diem Formula
Partial-Day Per Diem = Daily Rate × Partial Day Percentage% × Partial Days
Total Per Diem = Full-Day Per Diem + Partial-Day Per Diem
The calculator also shows an average per diem per day, which is useful for budgeting or comparing different trip lengths and policies.
Mode 2: Meals & Incidentals (M&IE)
Many per diem tables separate meals and incidentals from lodging. Employers may reduce per diem when some meals are provided by a conference, airline or client. The M&IE mode focuses on the daily meals and incidentals rate and includes a simple credit percentage for provided meals, plus an optional split between meals and incidentals.
M&IE Calculation
Adjusted M&IE = Total M&IE × (1 − Meals Provided Credit%)
Meals Portion = Adjusted M&IE × Meals Share%
Incidentals Portion = Adjusted M&IE − Meals Portion
This breakdown is helpful when comparing an all-inclusive hotel package against a per diem policy or when explaining to travelers how much of the allowance is meant for meals versus small daily expenses.
Mode 3: Lodging Per Diem
The lodging mode models nightly hotel costs under a per diem or rate cap. You enter the nightly rate, number of nights, local tax percentage and any fixed fees such as resort or service charges. The calculator returns base lodging cost, taxes, total cost and average cost per night.
Lodging Formula
Lodging Tax = Base Lodging Cost × Local Tax Rate%
Total Lodging Cost = Base Lodging Cost + Lodging Tax + Fixed Fees
Average Cost per Night = Total Lodging Cost ÷ Nights
This makes it easy to see whether a given hotel fits within the daily lodging cap or how room taxes affect total travel cost.
Mode 4: Partial Travel Days
Travel days often do not count as full per diem days. Many organizations pay a percentage of the full per diem on the first and last day to reflect partial travel. The partial-day mode lets you specify a full-day rate, first and last day percentages and the number of full days in between.
Partial Travel Day Formula
Last Day Per Diem = Full-Day Rate × Last Day Percentage%
Full-Day Per Diem Total = Full-Day Rate × Number of Full Days
Total Trip Per Diem = First Day + Last Day + Full-Day Total
By adjusting the percentages, you can simulate different policies and see the effect on total allowance for the same itinerary.
Mode 5: International Per Diem for Multi-Country Trips
When a traveler visits different cities or countries during one trip, each location may have its own per diem rate. The international mode allows you to specify up to three locations, each with a name, daily rate and number of days. The calculator sums the results, shows total travel days and calculates an overall average per diem per day.
International Per Diem Formula
Total Per Diem = Sum of All Location Allowances
Total Days = Sum of All Location Days
Average Per Diem per Day = Total Per Diem ÷ Total Days
The mode also indicates which location has the highest daily rate, useful when identifying the most expensive part of a trip or when comparing route options.
Why Use a Per Diem Calculator?
Per diem rules often look simple on paper, but real trips quickly become complicated: mixed domestic and international legs, conference-provided meals, hotel taxes and different lodging caps all interact with policy language. A calculator provides transparency and consistency.
Common use cases include:
- Employees estimating future reimbursement for a planned business trip.
- Freelancers and contractors pricing travel requirements into project quotes.
- HR and finance teams testing new per diem policies and daily rates.
- Travel managers comparing the cost of different destinations or itineraries.
- Organizations modeling the impact of changing partial-day percentages.
Limitations and Assumptions
This per diem calculator is a planning tool and does not represent any specific government or employer policy. Limitations include:
- Daily rates are not pre-loaded; you must enter rates from your official table or contract.
- Tax treatment of per diem, documentation requirements and maximum limits are not modeled.
- Provided meals are handled with a simple percentage credit, not per-meal deductions.
- Exchange rates for multi-currency trips are not included; all values are assumed in one currency.
Always review official travel policies, tax guidance and contractual obligations when finalizing reimbursements or allowances.
How to Use This Tool Effectively
- Start with the Standard Per Diem tab to get a quick estimate of total allowance for a single-rate trip.
- Use the M&IE tab when per diem separates meals and incidentals from lodging or when meals are provided.
- Switch to the Lodging tab to see how hotel choices and local taxes change total travel cost.
- Use the Partial Travel Days tab to align first and last day allowances with your policy.
- Plan multi-country or multi-city itineraries with the International Per Diem tab and compare scenarios.
- Save typical rate combinations for your organization so you can reuse them when planning similar trips.
Related Tools from MyTimeCalculator
If you are working on income and budgeting alongside travel, these tools can help:
Per Diem Calculator FAQs
Frequently Asked Questions About Per Diem and Travel Allowances
Find answers to common questions about how per diem works, how partial days are calculated and how to use this calculator with your own policy.
Per diem is a daily allowance for travel-related expenses such as meals, incidentals and lodging. Instead of reimbursing individual receipts, the traveler receives a fixed daily amount based on destination and policy rules.
The calculator uses adjustable percentages for first and last day per diem. The default is 75 percent of the full daily rate for each, but you can change this to match your employer or government policy.
No. You must copy the appropriate daily rates from official sources and enter them into the calculator. This approach keeps the tool flexible for any country, agency or private employer.
Yes. Separate modes cover meals and incidentals (M&IE) and lodging, and you can still use the standard per diem mode when your policy combines them into a single daily figure.
Yes. The international mode lets you define up to three locations, each with its own daily rate and days. The calculator then sums the total allowance and returns the overall average per diem per day.
No. It is an educational and planning tool. Tax treatment of per diem, documentation requirements and maximum allowed rates depend on local laws and should be confirmed with tax and legal professionals.